In the field of photographic processing, a photographic material, for example a film, is passed through one or more processing stages. Examples of such stages are development, bleach, bleach-fix, wash, fix and drying. The time spent in each of these stages depends on a number of factors, such as the type of material being processed and the temperature at which processing takes place.
In most existing photographic processing units, the photographic material passes relatively slowly through each stage so that it can spend as long as is desired in that stage, without the necessity of utilizing relatively large apparatus for each stage. This is the situation particularly in the case of minilab processors where it is important to restrict the total physical size of the apparatus as much as possible. This, however, has the disadvantage that the photographic material passes relatively slowly from one stage to the next, thus increasing the lengths of time during which no actual processing takes place.
Furthermore, the critical time in such apparatus is the time from when the first part of a photographic material enters the processor to when the last part of the material leaves the processor. This is known as the "access time". This can be seen to be the same as the sum of the "process time" (the period between the first part of a photographic material entering the processor and that part reaching the exit of the processor) and the time required to discharge the entire material from the processor. The "access time" is clearly increased by a relatively low linear speed.
To reduce the periods of time during which no actual processing takes place, and to reduce the "access time", it is therefore desirable to increase the linear speed at which the photographic material passes from one stage to the next and the rate at which it passes out of the processor.
However, if the path length traveled by the material in a stage is fixed, an increase in linear speed will reduce the period of time that the material spends in that stage. Similarly, altering the time spent by the material in one stage by altering the linear speed in that stage has the effect of altering the linear speed in any subsequent stages.
It is therefore desirable to utilize a system where the time spent in each stage and the linear speed out of the stages can be independently set.
By the very nature of the minilab, film fed in for processing is normally in the form of individual strips, rather than in the form of a continuous web formed of a large number of spliced strips, as is normally the case with large processing units. This necessitates the use of some form of device for feeding the strips into and through the apparatus.
U.S. Pat. No. 3,698,306 describes an arrangement in which photographic material is fed through guide means into a processing station and in which the photographic material is moved at a relatively high speed through the station. After the photographic material has left the station it is deflected by a deflector either back to the entrance of that station or on to the entrance of the next and passes through the atmosphere, even if it is being deflected back to the entrance of that station for a further cycle through that station. This has the disadvantage that no actual processing takes place during a period which is in effect a part of the processing cycle, as well as during the period when the photographic material is passing between stations. Furthermore, periods spent in the atmosphere can have adverse effects. For example developer will become increasingly oxidized.
According to one aspect of the present invention, there is provided apparatus for treating photographic material comprising:
at least one treatment station containing processing solution,
feed means for feeding the material into the treatment station,
cycling means for cycling the material around within the treatment station for a desired number of times, the material remaining submerged in the processing solution as it is cycled around within the treatment station,
guiding means for guiding the movement of the material within the station, and
deflecting means within the station for selectively deflecting the material so that it either remains within the station for a further cycle or exits from the station,
characterized in that the deflection of the material is caused by a change in the guiding means actuated by the deflecting means.
By this arrangement, the periods of time during which no actual processing takes place is substantially reduced. Furthermore, the periods of time spent in the atmosphere are also reduced.
Advantageously, the deflecting means comprises a member which is movable so as to align an inlet guide with a selected one of at least two outlet guides. The member may be provided with one or more further guides therein, the member being movable so as to selectively align one of the further guides with the inlet guide and with one of the outlet guides in order that the material passes along a desired path.
The member may be slidable, rotatable, or pivotable about a fixed point to provide the desired alignment.